Conduit is installed in a wide variety of construction projects ranging from residential and commercial buildings to transmission from central, electrical and communication distribution stations. After installation, the desired line must be run through the conduit. One common approach is to attach lightweight rope or cord onto a projectile which is inserted in one end of the conduit and driven through the conduit by air. The projectiles have taken several forms such as that of the drogue described in U.S. Pat. No. 6,932,323 to Benjamin James on Aug. 23, 2005 entitled “Drogue Having Based End Opening” where a flexible bag having an end opening allowing the bag to be inflated and pneumatically propelled along conduit, the bag bearing attached to and driving a biasing member which resiliently contacts the wall of the conduit. This device has the disadvantage of being relatively complex comprising two pieces which add to its cost and limits its flexibility within conduit.
Another prior device is described in U.S. Pat. No. 5,906,357 which issued on May 25, 1999 to Karl Munson, Sr. and is entitled “Conduit Torpedo Construction”. The title says it all as the patent describes a torpedo-like carrier for line through a conduit. The diameter of the torpedo has to match rather closely the inner diameter of the conduit as the torpedo is rigid or semi-rigid and appears to be relatively costly to make. A similar device is described in U.S. Pat. No. 4,498,659 which issued on Feb. 12, 1985 to Pete Brockelsby, III and is entitled “Conical Line-Pulling Carrier”. Again, a relatively rigid device is described which must match the inner diameter of the conduit and is relatively inflexible. The foregoing patents are exemplary of prior art devices which employ rigid or semi-rigid or inflexible line-pullers or torpedoes and are relatively costly. Accordingly, an object of my invention is to provide a line runner which is inexpensive, flexible, and easy to use.
In my earlier patent entitled “Apparatus and Method for Installing Line in Conduit” which is U.S. Pat. No. 4,596,381 that issued on Jun. 24, 1986, an inflatable bag is employed wherein the mouth of the bag may be shrunk around a holder for the line. The holder is a relatively rigid tube-like member which will keep the bag mouth open so that with the application of differential air pressure the bag will inflate and be propelled in the direction of the airflow. An object of my present invention is to eliminate the need for multiple piece construction for line carrier and, particularly, to eliminate the need for any rigid parts. Other advantages of my present invention will be better understood and appreciated by reference to the Summary of the Invention, Drawings, and Detailed Description which follow.